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Fajar Anggara
Department of Mechanical Engineering, Faculty of Engineering, Universitas Mercu Buana
Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Mechanical Engineering

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Bayesian networks approach on intelligent system design for the diagnosis of heat exchanger Dedik Romahadi; Fajar Anggara; Rikko Putra Youlia; Hifdzul Luthfan Habibullah; Hui Xiong
SINERGI Vol 26, No 2 (2022)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2022.2.001

Abstract

The heat exchanger highly influences the series of cooling processes. Therefore, it is required to have maximum performance. Some of the factors causing a decrease in its performance are increased pressure drop in the Plate Heat Exchanger (PHE), decreased output flow, leakage, flow obstruction, and mixing of fluids. Furthermore, it takes a long time to conclude the diagnosis of the performance and locate the fault. Therefore, this study aims to design an intelligent system for the performance diagnosis of the PHE using the Bayesian Networks (BNs) method approach. BNs are applied to new problems that require a new BNs network model. The system was designed using MSBNX and MATLAB software, comprising several implementation stages. It starts by determining the related variables and categories in the network, making a causality diagram, determining the prior probability of the variable, filling in the conditional probability of each variable, and entering evidence to analyze the prediction results. This is followed by carrying out a case test on the maintenance history to display the probability inference that occurs during pressure drop on the PHE. The result showed that the BNs method was successfully applied in diagnosing the PHE. When there is evidence of input in the form of a pressure drop, the probability value of non-conforming pressure-flow becomes 61.12%, PHE clogged at 73.59%, and actions to clean pipes of 70.18%. In conclusion, the diagnosis carried out by the system showed accurate results.
Effectiveness of capsules installation containing paraffin wax in a solar water heater Muhammad Nadjib; Wahyudi Wahyudi; Fajar Anggara; Yosua Heru Irawan
SINERGI Vol 26, No 2 (2022)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2022.2.012

Abstract

The encapsulation technique is one way to use latent heat storage material in a solar water heater tank. In this technique, several capsules may be arranged in the tank. In this study, the capsules were installed along the cross-section of the tank. There has been no discussion of which part of the capsule position has optimal heat energy with a capsule arrangement. Proper placement of the capsule arrangement can result in optimal thermal energy storage in the tank. This study aimed to investigate the effectiveness of installing capsules in a tank with different positions in terms of thermal energy storage. The study used an active solar water heater. The 24 capsules containing paraffin wax were arranged in a tank. The solar simulator was used as a heat source for the collector, and it was set at 1000 W/m2. The flow rate of water was 2 liters/minute. During the charging process, the water and paraffin wax temperature was recorded. The temperature evolution of water and paraffin wax obtained were used to analyze the thermal energy content. The results showed that the average heating rate for water and paraffin wax was 0.246 °C/min and 0.254 °C/min, respectively, so the capsule arrangement served as a suitable heat exchanger. The capsules installed at the top had an average heating rate increase of 111.4% compared to those at the bottom. Therefore, mounting the capsule at the top of the tank was more effective than placing it at the bottom. 
Angles of Tilted and Length of Resonator Effect on The Efficiency of A Close-Open-Type Thermoacoustic Rinasa Agistya Anugrah; Fajar Anggara
ROTASI Vol 25, No 2 (2023): VOLUME 25, NOMOR 2, APRIL 2023
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.25.2.1-8

Abstract

In determining the optimal design of the thermoacoustic engine, parameters were studied: tilt angle and resonator length. The purpose of this study is to find the highest efficiency in tilt angle and resonator length for a standing wave thermoacoustic engine (SWTE). The heat transfer properties therein were detected at three tilt angles of -90°, 0° and 90°, resulting in three resonator lengths variations such as 390, 780 and 1170 mm. This study was conducted to determine the magnitude of pressure amplitude using a two-pressure transducer method of recording by data acquisition and counting with Matlab software. The results of this study show that a tilt angle of 90° has the highest efficiency and a tilt angle of 0° has the lowest efficiency. A cavity length of 390mm yielded the highest SWTE efficiency, with an efficiency of 5.5%.
Co-Authors Hifdzul Luthfan Habibullah Hui Xiong Muhammad Nadjib Rikko Putra Youlia Rinasa Agistya Anugrah Romahadi, Dedik Wahyudi Wahyudi Yosua Heru Irawan